Abstract In order to study the engineering properties and characteristics of driving-induced subsidence of water-rich soft ground, the physical and mechanical parameters for the strata of the Shenzhen metro tunnel section from Guomao to Laojie were tested and analyzed by laboratory experiments. The results show that: (1) there are large pores and micro-fissures that are mutually connected, with high soil compressibility and consolidation settlement; (2) the ground is mainly composed of granular mixtures and has a high water and sand content, which leads to uncontrollable ground loss caused by construction drainage erosion; and (3) the low formation strength leads to poor stability of the surrounding rock during tunnelling. The above factors mean that this kind of ground has the obvious characteristics of a large disturbance scope, large ground settlement, and surface subsidence. Through actual measurement of ground settlement, the accuracy of the experimental results are verified; the maximum ground settlement caused by excavation of the Guomao-Laojie section is about 193.5mm, with a trough width of 80m, and surface subsidence occurring twice. Thus, the ground settlement caused by tunnel excavation is closely related to the geological conditions, and it is necessary and feasible to predict the ground settlement caused by tunnel excavation based on physical and mechanical properties.
Abstract：
In order to study the engineering properties and characteristics of driving-induced subsidence of water-rich soft ground, the physical and mechanical parameters for the strata of the Shenzhen metro tunnel section from Guomao to Laojie were tested and analyzed by laboratory experiments. The results show that: (1) there are large pores and micro-fissures that are mutually connected, with high soil compressibility and consolidation settlement; (2) the ground is mainly composed of granular mixtures and has a high water and sand content, which leads to uncontrollable ground loss caused by construction drainage erosion; and (3) the low formation strength leads to poor stability of the surrounding rock during tunnelling. The above factors mean that this kind of ground has the obvious characteristics of a large disturbance scope, large ground settlement, and surface subsidence. Through actual measurement of ground settlement, the accuracy of the experimental results are verified; the maximum ground settlement caused by excavation of the Guomao-Laojie section is about 193.5mm, with a trough width of 80m, and surface subsidence occurring twice. Thus, the ground settlement caused by tunnel excavation is closely related to the geological conditions, and it is necessary and feasible to predict the ground settlement caused by tunnel excavation based on physical and mechanical properties.
ZHANG Cheng-Ping,
ZHANG Ding-Li,
HAN Kai-Hang etc
.Study of Engineering Properties and Subsidence Characteristics after Driving of the Shenzhen Metro Tunnel in Water-Rich Soft Ground [J] MODERN TUNNELLING TECHNOLOGY, 2014,V51(4): 113-120
2014, Vol. 51 